SEE ALSO: Rainbow's Yoonhye expresses her wishes for Rottyful Sky to rest in peace

Yoonhye will play the kindhearted third daughter Young Sook for the first time on the October 11th filming. She previously made a cameo in the MBC Every1 idol drama 'The Dramatic', and after taking acting classes, she now joins fellow members Jaekyung, Woori, No Eul, and Seung Ah as an idol-turned-actress.

Yoonhye shared, "I am happy to make my acting debut in such an excellent production and role. Although I am lacking a lot, I will really work hard."

'The Firstborn', which began airing last month, portrays the inspirational story of 5 siblings who lose their parents and are raised by their eldest sibling.